Hun Sen said he was open to talks, but not with Sam Rainsy and his group.

PHNOM PENH —

Cambodian Prime Minister Hun Sen on Monday rejected a request from opposition leader Sam Rainsy for talks about the country's political problems, denigrating his archrival as a traitor and a convict.

Hun Sen was responding to a message posted Sunday on Twitter by Sam Rainsy, a founder of the Cambodia National Rescue Party, which called for negotiations to end a political crisis that has quashed many aspects of democracy, with the opposition party dissolved and its members thrown out of parliament.

FILE - Cambodian opposition leader Sam Rainsy delivers a speech to members of the Cambodia National Rescue Party (CNRP) at a hotel in metro Manila, Philippines, June 29, 2016.

Cambodian courts, generally considered to be under ruling party influence, last November sustained a government claim that the opposition party had conspired with foreigners to overthrow the ruling party.

A general election is scheduled for July, but with the absence of the Cambodia National Rescue Party, Hun Sen's Cambodia People's Party faces no credible challengers.

"I am always open to meeting with Hun Sen's government in order to find a peaceful solution to this unprecedented crisis, a solution that would be acceptable to both sides, with international guarantees," Sam Rainsy tweeted Sunday.

Hun Sen said he was open to talks, but not with Sam Rainsy and his group.

Speaking at a Buddhist ceremony on the outskirts of the capital, Phnom Penh, Hun Sen said he has spent more than half of his life negotiating for an end to conflict, an evident reference to his role in ending the threat posed by the communist Khmer Rouge, who after being ousted from power in the late 1970s carried out a guerrilla war. He said he was willing to hold talks for the sake of the country's peace and stability, but not with ``convicts'' and "traitors."

In recent years the opposition party has faced an onslaught of legal challenges from Hun Sen's government. Court rulings forced Sam Rainsy to remain in exile to avoid prison and pressured him into resigning from his party.

The attacks on the opposition culminated last November, when the Supreme Court ordered the Cambodia National Rescue Party to be dissolved for allegedly plotting to overthrow the government. Independent media have also been forced to shut down.

Kem Sokha, Sam Rainsy's successor as opposition leader, has been charged with treason for allegedly conspiring with the United States to topple the government, and now faces up to 30 years in prison if convicted. He was arrested on the basis of videos from several years ago showing him at a seminar where he spoke about receiving advice from U.S. pro-democracy groups. The opposition party denied the treason allegation, saying it was politically motivated.

FILE - Supporters of Kem Sokha, leader of the Cambodia National Rescue Party, stand outside the Appeal Court during a bail hearing for the jailed opposition leader in Phnom Penh, Sept. 26, 2017.

Hun Sen said Monday he will not ask King Norodom Sihamoni to grant an amnesty to Kem Sokha, who is in detention awaiting trial.

Choung Chou Ngy, a lawyer for Kem Sokha, said Sunday his client has high blood pressure and diabetes, and has fallen sick and weak in prison.

The lawyer said his defense team submitted a request two weeks ago for the court to give Kem Sokha permission to go to Singapore for medical treatment, but there had been no reply.

Hun Sen has been in power for three decades, maintaining a framework of democracy while exercising near-total control. His grip seemed shaken in 2013's general election, when the Cambodia National Rescue Party mounted a strong challenge, winning 55 seats in the National Assembly and leaving Hun Sen's party with 68.